Abstract: A method of detecting sulfotransferase activity including conducting a first reaction comprising, measuring free phosphate produced by the first reaction, and comparing the measured free phosphate to a free phosphate standard curve or equation or to a free phosphate level obtained in a separate reaction. The first reaction includes combining the sulfotransferase, Golgi-resident PAP-phosphatase (gPAPP), a 5?-nucleotidase, a substrate of the sulfotransferase, and 3?-phosphoadenosine-5?-phosphosulfate (PAPS) under conditions to produce 3?-phosphoadenosine-5?-phosphate (PAP).

Abstract: Assays and methods for detecting and/or quantifying activity of a test sulfotransferase comprising by releasing a free phosphate from the PAP produced by the sulfotransferase reaction and detecting the free phosphate. The assay can includes gPAPP, a free phosphate detector and an optional control sulfotransferase. The method includes combining a test sulfotransferase with the substrate of the sulfotransferase, PAPS and gPAPP and detecting the free phosphate. The level of free phosphate directly correlates to the activity of the sulfotransferase. The assay and methods can be used to screen agents for their effect upon sulfotransferase activity.

Abstract: A pre-determined concentration of stabilized, maturation-arrested porcine reticulocytes in a red blood cell base, useful as a reticulocyte control composition. The composition can be provided in the form of a concentrated reticulocyte composition, to be diluted to a desired final reticulocyte concentration at the time of use. The composition can also be provided in the form of a diluted, ready-to-use control composition. Also included is a method of preparing such a composition, the method involving sequential steps of forming and sedimenting Rouleaux bodies.

Abstract: A pre-determined concentration of stabilized, maturation-arrested porcine reticulocytes in a red blood cell base, useful as a reticulocyte control composition. The composition can be provided in the form of a concentrated reticulocyte composition, to be diluted to a desired final reticulocyte concentration at the time of use. The composition can also be provided in the form of a diluted, ready-to-use control composition. Also included is a method of preparing such a composition, the method involving sequential steps of forming and sedimenting Rouleaux bodies.

Abstract: A vector system that allows the rapid and effective screening of recombinant constructs. The vector system includes a marker protein useful for identifying transfected cell lines, wherein the promoter used to express the marker protein has be substantially weakened in comparison to its corresponding wild type form.